Tankless Coil

[olimazi]

I have an older oil fired boiler with a tankless coil for hot water.
It's clogged with minerals and I get low flow on the hot (cold is OK).
No plumber will touch it in fear that it will break the boiler - what are my options here? Flush it with acid? Try and remove it and risk damaging the boiler? Screw it and install an electric hot water tank?
Any help would be appreciated.

 

[johnjh2o]

1- Flush it with acid. Not something to be done by a DIY and the condition will return.
2- Try to remove it. Are you saying to replace it with a new coil? If so the condition will return.
3- Install a electric water heater. That will solve your problem but your cost of making hot water will increase.

What I would suggest doing is to install a indirect water heater. Your operating cost will be much lower, even lower then they are with your current system. (which is not good by today's standers)

Amtrol- Indirect Water Heaters

John

 

[olimazi]

I always thought an indirect would be best for newer efficient boilers... mine is very old and only about 80% efficient.
Why do you say the acid flush is not diy?

I was gonna get a small transfer pump 1/10 hp, 2 washing machine hoses and a bucket - then flush some kind of lime remover solution from the cold side out the hot side. I have isolation valves in place. Then flush it good w/ water. Of course shut the boiler off first and drain the coil. Dunno, sounds pretty easy - not planning to use a harsh acid like hydrochlric/muriatic... something milder like sulfamic mixture.

The coil has been replaced before-I can see newer piping on the unit. I think it would be easier for me to flush than remove the old one and screw in a new one-it's a 5" diameter and getting a big wrench in there wont be easy.

 

[johnjh2o]

I have flushed many coils and unless you do something about your water condition you will be right back where you are now, but in less time then it took to plug the coil the first place. There a pumps that are made just for that purpose. Even at that we would get at the most three coil cleanings before the pump failed. What you have is one of the most costly ways to make hot water. Your boiler can handle a indirect water heater, it may not be as efficient as a newer one but you will be saving on your hot water costs until you see fit to replace it.

John

 

[olimazi]

How long do you think the acid flush will last? We're only planning on being in the house 2 years.
Also, what solution have you used? Do you think I'll be wasting my time w/ CLR?

 

[Caduceus]

I don't want to steal the thread from john, but you have to understand that to predict what type of life expectancy that your system would have from the service is impossible to determine. I have met many customers in the past who have planned short-term on repairs and found that it lasted even less time than predicted. It usually resulted in more money and time spent with the same result as if they had done it right the first time. Though I may not be as experienced in this facet of plumbing as john is, I agree with the advice he has given.

 

[johnjh2o]

What we used was lime solvent. As far as how long the cleaning will last depends on your water condition. This stuff is very strong, if spilled on a concrete floor it would etch it. The fumes or very strong, and if you get some on your clothing it will destroy them. That is the reason I said it is not a DIY job. I'm giving you a link to a PDF for this stuff and I strongly advise you not to use it. If your going to be selling the home in the near future then put in a electric water heater and be done with it.
I don't think you will have much luck using CLR.

http://www.unitedwallsystems.com/download/SK_101_Lime_Solvent_PDS_081508_C.pdf

John

P.S. we used it full strength.

 

[johnjh2o]

Caduceus: Thank you for your comments. Flushing coils was one of the worst jobs we had to do. It reached a point were we would no longer do it because of the hazards involved handling the solvent.

John

 

[olimazi]

Thanks for the input guys - I think we will go with the 40 gal electric tank - I'm assuming it will be more efficient than the coil as well, since heating oil was around $4/gal her this winter (electricity runs about 20 cents per KW/hr here, so I figured a 4500W tank would run me about $80/month).
Now the tank should be a fairly easy DIY job for 2 guys and a case of beer, eh?

 

[johnjh2o]

In your case I think you made the correct decision. I also don't think it will cost you $80.00 a month. But I could be wrong on that.
Good luck with your new heater.

John